Tissue fixation device

ABSTRACT

A tissue fixation device is provided that is preferably used to secure a ligament or graft within a prepared bone tunnel, for example in ACL replacement. The tissue fixation device generally includes an elongate member having a shaft portion that is adapted to be at least partially disposed within a bone tunnel, and a guide member that forms a portion of the proximal end of the elongate member. The guide member has a graft-seating surface that is effective to seat a graft and to position the graft toward one side of a bone tunnel when the device is disposed within the bone tunnel. The device also includes a graft-retaining member formed on at least a portion of the graft-seating surface.

FIELD OF THE INVENTION

[0001] The present invention relates to tissue fixation devices, and inparticular to a ligament anchor device for use in arthroscopic surgicalprocedures.

BACKGROUND OF THE INVENTION

[0002] The complete or partial detachment of ligaments, tendons or othersoft tissues from their associated bones within the body is a relativelycommon injury, particularly among athletes. Such injuries generallyresult from excessive stresses being placed on these soft tissues. Forexample, a tissue-detaching injury may occur as the result of anaccident such as a fall, overexertion during a work-related activity,during the course of an athletic event, or in any one of many othersituations and/or activities.

[0003] In the case of a partial detachment, commonly referred to underthe general term “sprain,” the injury will frequently heal itself, ifgiven sufficient time, and if care is taken not to expose the injury toany undue or extraordinary stress during the healing process. If,however, the ligament or tendon is completely detached from itsassociated bone or bones, or if it is severed as the result of atraumatic injury, partial or permanent disability may result.Fortunately, a number of surgical techniques exist for re-attaching suchdetached tissues and/or completely replacing severely damaged tissues.

[0004] One such technique involves the re-attachment of the detachedtissue using traditional attachment devices such as metal staples,sutures, and cancellous bone screws. Such “traditional” attachmentdevices have also been used to attach tendon or ligament substitutes(often formed of autogenous tissue harvested from elsewhere in the body)to the desired bone or bones. Another technique is described in detailin U.S. Pat. No. 4,950,270 entitled “Cannulated Self-Tapping Bone Screw”issued Aug. 21, 1990 to Bowman et al., which is incorporated herein byreference in its entirety. In this technique, an anterior cruciateligament in a human knee, for example, is replaced and/or repaired byforming bone tunnels through the tibia and/or femur at the points ofnormal attachment of the anterior cruciate ligament. A ligament graft,with a bone plug on at least one of its ends, is sized to fit within thebone tunnels. Suture is then attached to the outer end of each boneplug, and thereafter passed through the femoral and/or tibial bonetunnels. The femoral plug and/or the tibial plug is/are then insertedinto the appropriate bone tunnel behind the suture. Subsequently, thesuture is drawn tight (simultaneously in opposite directions, in caseswhere bone plugs are to be located in both a femoral bone tunnel and atibial bone tunnel). This procedure positions the bone plug (or plugs)in the desired location, and imparts the desired degree of tension tothe ligament or ligament substitute. Finally, while holding the boneplugs in position, a bone screw is inserted between each bone plug andthe side wall of its associated bone tunnel so as to securely lock thebone plug in position using a tight interference fit.

[0005] With the advancement of anterior cruciate ligament surgery fromthe open reconstructions to arthroscopic-endoscopic reconstructions,surgeons are faced with a number of choices concerning graft fixation,both at the femur and the tibia. These ligament fixation devices havebeen introduced to the orthopaedic community, often with mechanicalstudies that bear little relevance to the actual demands of postsurgicalrehabilitation and return to sports mechanics. Thus, it can be difficultfor the surgeon to determine those fixation devices that will prove themost reliable during early healing stages.

[0006] A number of principles have been established in the last decadeconcerning anterior cruciate ligament (ACL) surgery, which when adheredto usually result in an excellent outcome. Anatomic placement, nofemoral condylar notch impingement, early range of motion, and strong,rigid fixation are but a few of these important principles. Some currentdevices, however, cannot withstand repeated cycling motions without lossof fixation strength. Moreover, depending on the fixation point of thegraft within the bone tunnel, the graft can wear against the boneeventually resulting in tearing or breakage of the graft.

[0007] Accordingly, there is a need for an improved tissue fixationdevice that provides a strong, rigid fixation, and that avoids the riskof tearing or breakage of the graft.

SUMMARY OF THE INVENTION

[0008] The present invention generally provides a tissue fixation devicehaving an elongate member adapted to be at least partially disposedwithin a bone tunnel and including proximal and distal ends with alongitudinal axis extending therebetween. A guide member, which isformed on a portion of the proximal end of the elongate member, includesa graft-seating surface effective to seat a graft and to position thegraft toward one side of the bone tunnel when the tissue fixation deviceis disposed within the bone tunnel. The device further includes agraft-retaining member formed on at least a portion of the graft-seatingsurface.

[0009] In one embodiment, the graft-seating surface of the guide membercan be substantially planar and an opposed, bone-contacting surface canbe substantially convex. A proximal end of the guide member canoptionally have a substantially hemispherical cross section. The guidemember can also include a height and a width that increases in adistal-to-proximal direction. Preferably, at least a portion of thegraft-seating surface extends along an inclined plane that intersectsthe longitudinal axis. In an exemplary embodiment, the inclined portionof the graft-seating surface extends at an angle in the range of about5° to 45°.

[0010] In another embodiment, the graft-retaining member can be in theform of an eyelet adapted to receive and retain a graft. The opening inthe eyelet preferably defines an axis extending therethrough that issubstantially transverse to the longitudinal axis of the elongatemember. The graft-retaining member can optionally extend between theproximal end of the elongate member and the graft-seating surface of theguide member. In particular, a first wall can be mated to the proximalend of the elongate member and can extend in a direction substantiallyparallel to the longitudinal axis, and a second wall can be mated to thegraft-seating surface of the guide member and can extend in a directionsubstantially transverse to the first wall. In one embodiment, thegraft-retaining member defines a substantially rectangular-shapedopening for receiving and retaining a graft.

[0011] In other aspects, the distal end of the elongate member can beadapted to be disposed within an expandable sleeve that is able to bedisposed within a bone tunnel. The distal end of the elongate member caninclude sleeve-expanding ridges that assist in securing the elongatemember within a bone tunnel. Each ridge is preferably in the shape ofwedge-like member circumferentially formed about the distal end of theelongate member and having a diameter that increases distally toproximally.

[0012] In yet another embodiment, at least one suture-receivingstructure can be formed on the guide member to receive suture to securea graft to the guide member. The suture-receiving structure preferablycomprises first and second bores extending through the guide member fromthe graft-seating surface to an opposed, bone-contacting surface in adirection substantially transverse to the axis of the elongate member.The suture-receiving structure can further include a trough formed inthe bone-contacting surface and extending between the first and secondbores.

[0013] In another embodiment, the present invention provides a tissuefixation device that is adapted to anchor soft tissue to bone. Thedevice includes an elongate member having a distal shaft with aproximal, graft-retaining head disposed thereon. A longitudinal axisextends through the elongate member. A wedge-shaped guide member extendsproximally from the graft-retaining head and includes an inclinedgraft-seating surface oriented in a plane that intersects thelongitudinal axis of the elongate member. The graft-seating surface iseffective to orient and maintain a graft in a desired position. Thegraft-seating surface can have a variety of configurations, but ispreferably substantially planar and includes an opposed, bone-contactingsurface having a hemispherical shape.

[0014] The present invention also provides methods for attaching atissue graft to bone.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention will be more fully understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

[0016]FIG. 1A is a perspective view of one embodiment of a tissuefixation device according to the present invention;

[0017]FIG. 1B is a side view of the tissue fixation device shown in FIG.1A;

[0018]FIG. 2 is a proximal end view illustration of an opening of a bonetunnel having the tissue fixation device of FIG. 1A and a graft disposedtherein;

[0019]FIG. 3A is a chart illustrating an exemplary procedure forimplanting a device according to the present invention; and

[0020]FIG. 3B is a side view illustration of the tissue fixation deviceof FIG. 1A disposed within an expandable sleeve in a bone tunnel formedin a patient's femur.

DETAILED DESCRIPTION OF THE INVENTION

[0021] In general, the present invention provides a tissue fixationdevice that is preferably used to secure a ligament or graft within aprepared bone tunnel, for example in ACL replacement. As shown in FIG.1A, the tissue fixation device 10 generally includes an elongate memberhaving proximal and distal ends 10 a, 10 b. The distal portion is in theform of a shaft portion 12 that is adapted to be at least partiallydisposed within a bone tunnel, and a guide member 14 forms a portion ofthe proximal end of the elongate member. The guide member 14 has agraft-seating surface 22 effective to seat a graft and to position thegraft toward one side of a bone tunnel when the device 10 is disposedwithin the bone tunnel. The device 10 also includes a graft-retainingmember 16 formed on at least a portion of the graft-seating surface 22.The tissue fixation device 10 is particularly advantageous in that thegraft guide 14 provides a strong, rigid fixation, and avoids compressionof the graft by preventing the graft from wearing against the edge ofthe bone tunnel, which can eventually result in tearing or breakage ofthe graft. While the tissue fixation device 10 is described for use inACL surgery, a person skilled in the art will appreciate that the device10 can be used for a variety of medical purposes.

[0022] The shaft portion 12 of the device 10 can have a variety ofconfigurations, and can be adapted to be embedded directly into a bonetunnel, or alternatively it can be adapted to be disposed within anotherimplant (e.g., a sleeve) to facilitate the secure placement of thetissue fixation device within the bone tunnel. Preferably, the device 10is used with a sleeve, such as the sleeve shown in FIG. 3 and describedin U.S. Pat. No. 4,870,957 of Goble et al., which is incorporated hereinby reference in its entirety. As shown in FIGS. 1A and 1B, the shaft 12can include a series of sleeve-expanding ridges 13 that assist insecuring the shaft 12 within a sleeve 18. Each ridge 13 can have avariety of shapes and sizes, but preferably each ridge 13 is in theshape of a wedge-like member circumferentially formed about the shaft12, and having a diameter d_(r) that increases in a distal-to-proximaldirection. The shaft 12 can also optionally include a transverse bore20, or similar structure, formed therein for receiving a suture whichcan be used to pull the device 10 through a bone tunnel and into thesleeve 18.

[0023] The guide member portion 14 of the device 10 is positionedproximal to the shaft 12, and forms the proximal head of the device 10.The guide member 14 can have a variety of configurations, shapes, andsizes, but it should be designed to be effective to seat a graft and toposition the graft toward one side of a bone tunnel when the tissuefixation device 10 is disposed within the bone tunnel. In oneembodiment, the guide member extends a distance beyond thegraft-retaining member 16 in a proximal direction to form an extensionmember on the device 10. This extension of the device allows the device10 to be inserted further into a bone tunnel, thereby providing astrong, rigid fixation, and provides an additional surface for the graftto rest on.

[0024]FIGS. 1A and 1B illustrate an exemplary embodiment of a guidemember 14 having a generally elongate shape and including asubstantially planar, graft-seating surface 22, an opposed,bone-contacting surface 26 that has a substantially convex shape, and aproximal end wall 24 having a hemispherical shape. The proximal portion22 b of the guide member 14 can have a flared or wedge-like shape tofacilitate the placement of a graft disposed on the graft-seatingsurface 22 toward one side of a bone tunnel when the tissue fixationdevice 10 is disposed within the bone tunnel. This is furtherillustrated in FIG. 2, which shows the proximal end surface 24 of theguide member 14 having a substantially hemispherical shape, so as tooccupy about one-half of the bone tunnel 30, thereby forcing the graft32 to remain in the other half of the bone tunnel 30.

[0025] The wedge-like or flared shape of the proximal portion, shown inmore detail in FIG. 1B, can be achieved by providing a graft-seatingsurface 22 having a distal portion 22 a with a substantially constantheight H₁ and a proximal portion 22 b with a height H₂ that increases ina distal-to-proximal direction. The angle α of the proximal,graft-seating surface 22 b, e.g., the inclined portion, can vary, but inan exemplary embodiment the proximal graft-seating surface 22 b extendsat an angle α in the range of about 5° to 45°. Referring back to FIG.1A, the proximal graft-seating surface 22 b also includes a width W₂that can increase in a distal-to-proximal direction, and the distalgraft-seating surface 22 a can have a substantially constant width W₁.

[0026] A person skilled in the art will appreciate that thegraft-seating surface 22 can vary in shape and size, and can have asubstantially constant height and width, or a height and width thatvaries between the proximal and distal ends 14 a, 14 b of the guidemember 14. Moreover, the device 10 is not limited to having ahemispherical sidewall, but rather can include any number of sidewallshaving any sidewall shape. The device 10 can also optionally includeother features, such as bone-engaging surface features, formed on thesidewall(s) to facilitate the secure placement of the device 10 within abone tunnel.

[0027] In an exemplary embodiment, the guide member 14 can also includefirst and second bores 36 a, 36 b extending through the graft-seatingsurface 22 to the opposed, bone-contacting surface 26 in a directionsubstantially transverse to the longitudinal axis L of the device 10.The guide member 14 can also optionally include a trough 38, shown inFIG. 1B, formed in the bone-contacting surface 26 and extending betweenthe first and second suture-receiving bores 36 a, 36 b. The trough 38 iseffective to seat the suture sub-flush with the bone-contacting surface26, thus preventing movement of the suture along the convexbone-contacting surface 26, and preventing the suture from coming intocontact with the bone tunnel. In use, two free ends of a suture arepassed through the bores 36 a, 36 b such that a portion of the sutureextending between the free ends rests in the trough 38. The free ends ofthe suture can then be tied around a graft to secure the graft to thegraft-seating surface 22 of the guide member 14. A person skilled in theart will appreciate that a variety of alternative techniques can be usedto secure one or more grafts to the graft-seating surface 22 of guidemember 14.

[0028] Referring back to FIG. 1A, the device 10 further includes agraft-retaining member 16 formed on at least a portion of thegraft-seating surface 22. In an exemplary embodiment, thegraft-retaining member 16 is formed on the distal portion 22 a of theguide member 12 to allow a graft to be looped through thegraft-retaining member 16 and to rest on the graft-seating surface 22.The graft-retaining member 16 can have a variety of configurations,shapes, and sizes. As shown in FIG. 1A, the graft-retaining member 16 isgenerally in the form of an eyelet having an opening 34 adapted toreceive a graft. The eyelet is formed from a first, longitudinal wall 16a that extends between a proximal end of the shaft 12 and that mates toa second, substantially transverse wall 16 b that is joined to thegraft-seating surface 22. The first and second walls 16 a, 16 b can beintegrally formed with one another, as well as with the guide member 14and/or the shaft 12 (i.e., as a result of a molding process). Moreover,the shape of each wall 16 a, 16 b, as well as the shape of the opening34 defined by the walls 16 a, 16 b, can vary. In one embodiment,however, the walls 16 a, 16 b that form the graft-retaining member 16are slightly rounded or curved to prevent damage to a graft disposedthrough the opening 34 formed by the walls 16 a, 16 b. The walls 16 a,16 b also preferably form an opening 34 having a shape and size thatfacilitates placement of a graft therethrough. As shown in FIG. 1A, theopening 34 has a substantially rectangular shape. The position of theopening 34 can also vary, but preferably the opening 34 defines an axisT that extends in a direction substantially transverse to a longitudinalaxis L of the device 10. This further facilitates placement of a graftthrough the opening 34, and placement of the two free ends of the graftonto the graft-seating surface 22 of the guide member 14, as shown inFIGS. 2 and 3.

[0029] A person skilled in the art will appreciate that a variety ofgraft-retaining members can be used with the device 10 of the presentinvention. By way of non-limiting example, the graft-retaining membercan have a partially open, hook-like configuration, or any otherconfiguration that allows a graft to be retained by the device 10.

[0030]FIGS. 3A and 3B illustrate an exemplary embodiment for using thedevice 10 to repair an anterior cruciate ligament. Soft tissue grafts,such as the semitendinosus, can be attached to the graft-retainingmember 16, preferably by quadrupling the graft through thegraft-retaining member 16, or by combining tendons that are doubledthrough the graft-retaining member 16. A whip stitch can be used tofacilitate pulling of the graft through the graft-retaining member 16.Once the graft is threaded through the graft-retaining member, the graft32 is then pulled in a proximal direction to cause the graft 32 to reston the graft-seating surface 22, as shown in FIG. 3B. The graft 32 canoptionally be secured to the graft-seating surface 22 using one or moresutures that are passed through suture-receiving structures, such asfirst and second bores 36 a, 36 b described above with respect to FIG.1A. Once the graft is attached to the device 10, the graft and thedevice 10 are passed through a sizer to determine the appropriatediameter of the femoral and tibial tunnels.

[0031] In drilling the tunnel, it is extremely important that theentrance of the tibial tunnel to the knee be located accurately inrelationship to the femoral notch. The usual position is slightlymedial, approximately 5 millimeters from the posterior cruciate ligamentand in the posterior portion of the native ACL footprint. The tip of atibial guide, such as the Innovasive ACL tibial Guide manufactured byMitek of Westwood, Mass., is inserted through the interior medial portaland locked on the tibia. A pin is then drilled in a proximal direction,as shown in FIG. 3A(1) at approximately a 45° angle to the horizontalaxis of the tibial plateau. After the pin emerges in the intercondylarnotch, the guide is removed and pin placement is visually checked bytaking the knee through a range of motion. Once an acceptable positionhas been confirmed, the pin is further driven across the intercondylarnotch and into the back of the femoral notch to properly mark the anglethat the ACL graft will traverse as it proceeds from the tibia to thefemur. The tibial tunnel and femoral attachment site for the graft onthe lateral condylar notch can then be reamed around the guide pin, asshown in FIG. 3A(2). Another drill tip can then be passed over the pinthrough the tibial tunnel to create a socket in the femoral condyle forreceiving sleeve 18, as shown in FIG. 3A(3). A pilot hole can then betapped as shown in FIG. 3A(4), and sleeve 18 can be screwed intoposition as shown in FIG. 3A(5).

[0032] With the sleeve in place, an arthroscope can be inserted throughthe tibial tunnel, and the knee can be taken through a range of motion.If the intercondylar notch is seen impinging or overlapping the tibialtunnel, further notch plasty can be completed at this time. Once thenotch-graft fit has been confirmed using the arthroscope, the pin ispushed retrograde, emerged distally through the tibial tunnel. Thetissue fixation device 10 can now be pulled into the joint using thesuture attached to the transverse bore 20 in the shaft 12, and attachedto the pin. The pin exits the superior thigh, pulling the suture and thedevice 10 through the tibial tunnel into the sleeve 18, as shown in FIG.3A(6). As the device 10 is pulled into the sleeve 18, the ridges 13expand the sleeve 18 to engage the sleeve 18 to create an interferencewithin the bone tunnel to prevent removal of the sleeve 18 and thefixation device 10 from the bone tunnel. Alternatively, or in addition,a pronged inserter (not shown) or similar tool may be used to push thedevice 10 into the sleeve 18.

[0033] The tissue fixation device 10 is preferably positioned within thebone tunnel such that the proximal end wall 24 of the guide member 14 iseither aligned with the opening of the bone tunnel, or is disposed justwithin the opening of the bone tunnel, as shown in FIG. 3B. Moreover,the guide member 14 should be aligned within the tunnel (as shown inFIG. 3B) such that bending of the patient's knee will cause the graft 32to the tension over the proximal end 14 a of the guide member 14, ratherthan to tension against the edge of the opening of the bone tunnel whichcan potentially damage the graft 32. To complete the procedure, theremaining end of the graft is tension to and affixed to the anteriortibia using, for example, a screw and washer.

[0034] The device 10 can be formed from a variety of materials, and canbe formed from separate parts which are mated to one another.Preferably, however, the device 10 is formed as a single unit from amaterial that is suitable for human implantation, such as metal orplastic, and that is somewhat resilient. Exemplary materials include,for example, metal, absorbable polymers, such as, but not limited to,polylactic acid, polyglycolic acid, and copolymers thereof,non-absorbable polymers, such as, but not limited to, polyethylene,polypropylene, and acetal, and biocomposite materials, such as blends ofpolymers containing tricalcium phosphate and hydroxy appetite.

[0035] One of ordinary skill in the art will appreciate further featuresand advantages of the invention based on the above-describedembodiments. Accordingly, the invention is not to be limited by what hasbeen particularly shown and described, except as indicated by theappended claims. All publications and references cited herein areexpressly incorporated herein by reference in their entirety.

What is claimed is:
 1. A tissue fixation device, comprising: an elongatemember adapted to be at least partially disposed within a bone tunneland having proximal and distal ends with a longitudinal axis extendingtherebetween; a guide member forming a portion of the proximal end ofthe elongate member, the guide member having a graft-seating surfaceeffective to seat a graft and to position the graft toward one side ofthe bone tunnel when the tissue fixation device is disposed within thebone tunnel; and a graft-retaining member formed on at least a portionof the graft-seating surface.
 2. The device of claim 1, wherein thegraft-seating surface of the guide member is substantially planar and anopposed, bone-contacting surface is substantially convex.
 3. The deviceof claim 2, wherein the guide member has a height and a width thatincreases in a distal-to-proximal direction.
 4. The device of claim 2,wherein the guide member has a height that increases in adistal-to-proximal direction.
 5. The device of claim 1, wherein theguide member includes a proximal end having a substantiallyhemispherical cross section.
 6. The device of claim 1, wherein at leasta portion of the graft-seating surface extends along an inclined planethat intersects the longitudinal axis.
 7. The device of claim 6, whereinthe inclined portion of the graft-seating surface extends at an angle inthe range of about 5° to 45°.
 8. The device of claim 1, wherein thegraft-retaining member is in the form of an eyelet adapted to receiveand retain a graft.
 9. The device of claim 8, wherein an opening in theeyelet that has an axis extending therethrough that is substantiallytransverse to the longitudinal axis of the elongate member.
 10. Thedevice of claim 1, wherein the graft-retaining member extends betweenthe proximal end of the elongate member and the graft-seating surface ofthe guide member.
 11. The device of claim 10, wherein thegraft-retaining member includes a first wall mated to the proximal endof the elongate member and extending in a direction substantiallyparallel to the longitudinal axis, and second wall mated to thegraft-seating surface of the guide member and extending in a directionsubstantially transverse to the first wall.
 12. The device of claim 11,wherein the graft-retaining member defines a substantiallyrectangular-shaped opening for receiving and retaining a graft.
 13. Thedevice of claim 1, wherein the distal end of the elongate memberincludes a plurality of ridges that assist in securing the elongatemember within a bone tunnel.
 14. The device of claim 13, wherein each ofthe plurality of ridges is in the shape of wedge-like membercircumferentially formed about the distal end of the elongate member,each wedge-like member having a diameter that increases distally toproximally.
 15. The device of claim 1, wherein the distal end of theelongate member is adapted to be disposed within an expandable sleevethat is able to be disposed within a bone tunnel.
 16. The device ofclaim 1, further comprising at least one suture-receiving structureformed on the guide member and adapted to receive suture to secure agraft to the guide member.
 17. The device of claim 16, wherein thesuture-receiving structure comprises first and second bores extendingthrough the guide member from the graft-seating surface to an opposed,bone-contacting surface in a direction substantially transverse to theaxis of the elongate member.
 18. The device of claim 17, wherein thesuture-receiving structure further comprises a trough formed in thebone-contacting surface and extending between the first and secondbores.
 19. The device of claim 1, further comprising a substantiallyplanar, circular head formed on the proximal end of the elongate member,the guide member and the graft-retaining member each being mated toopposed sides of the head.
 20. The device of claim 1, further comprisinga transverse bore extending through the distal end of the elongatemember for receiving a suture.
 21. A tissue fixation device adapted toanchor soft tissue to bone, comprising: an elongate member having adistal shaft with a proximal, graft-retaining head disposed thereon, theelongate member having a longitudinal axis extending therethrough; and awedge-shaped guide member extending proximally from the graft-retaininghead and including an inclined graft-seating surface oriented in a planethat intersects the longitudinal axis of the elongate member, thegraft-seating surface being effective to orient and maintain a graft ina desired position.
 22. The device of claim 21, wherein thegraft-seating surface of the guide member is substantially planar and anopposed, bone-contacting surface is substantially convex.
 23. The deviceof claim 21, wherein the guide member includes a proximal end having asubstantially hemispherical cross section.
 24. The device of claim 21,wherein the graft-retaining member is in the form of an eyelet adaptedto receive and retain a graft.
 25. The device of claim 24, wherein anopening in the eyelet has an axis extending therethrough that issubstantially transverse to the longitudinal axis of the elongatemember.
 26. The device of claim 21, wherein the distal shaft of theelongate member includes a plurality of ridges that assist in securingthe elongate member within a bone tunnel.
 27. The device of claim 21,wherein the distal end of the elongate member is adapted to be disposedwithin an expandable sleeve that is able to be disposed within a bonetunnel.
 28. The device of claim 21, further comprising at least onesuture-receiving structure formed on the guide member and adapted toreceive suture to secure a graft to the guide member.
 29. The device ofclaim 28, wherein the suture-receiving structure comprises at least onebore extending through the guide member from the graft-seating surfaceto an opposed, bone-contacting surface in a direction substantiallytransverse to the axis of the elongate member.
 30. A method of attachinga tissue graft to bone, comprising the steps of: forming a bone tunnelinto a bone; providing a tissue fixation device having an elongatemember adapted to be at least partially disposed within a bone tunnel, aguide member forming a portion of a proximal end of the elongate member,the guide member having a graft-seating surface effective to seat agraft and to position the graft toward one side of the bone tunnel whenthe tissue fixation device is disposed within the bone tunnel, and agraft-retaining member formed on at least a portion of the graft-seatingsurface; attaching a tissue graft to the graft-retaining member; andinserting the tissue fixation device into the bone tunnel with thetissue graft extending from an open end of the bone tunnel andpositioned toward one side of the bone tunnel to thereby attach thetissue graft to the bone.
 31. The method of claim 30, wherein the tissuefixation device is inserted into an expandable sleeve disposed withinthe bone tunnel to lock tissue fixation device in the bone tunnel. 32.The method of claim 30, furthering comprising the step of securing thetissue graft to the graft-seating surface of the guide member by tyingone or more sutures around the graft and the guide member prior toinserting the tissue fixation device into the bone tunnel.
 33. Themethod of claim 30, wherein the bone tunnel is formed in the tibia andthe tissue graft is used to repair a patient's cruciate ligament.